This document describes the various guages on an e-series vehicle and how to connect an aftermarket guage using the existing wiring looms and sensors. While this doco was taken from an ED, the basic principles are the same on most Falcons. However it would be wise to check before attempting any 3rd party wiring on your car.

Things to think about before starting:

In terms of cable to use for this, figure 8 will be fine for all the gauges listed here.

Crimps are a good idea when needed, but only good ones. Crappy crimps never work, and they're more trouble than they're worth. So make sure you get some good quality crimps and a good crimping tool.

Soldering iron, solder, and some electrical tape is essential. If you're going to do a job, do it right!

Sidecutters and wire strippers are also needed. I use my Leatherman for all my stripping and cutting.

Heatshrink makes things look neat and attractive. Very good idea in the engine bay, or anywhere where the cable is visible.

Disconnect the negative terminal of the battery. Shorts are bad. Especially when your leatherman almost gets welded to the chassis. Bad experience. Play it safe. All this stuff is expensive so it's worth the extra 2 minutes work.

TachometerWhat it does: A tacho measures the speed that the ignition system is sparking at. Faster sparking = faster engine speed. It does this by connecting its signal wire (usually green) to the negative terminal on the low tension (thinner wire) side of the ignition coil.

Wiring it up: There are 4 wires on most tachos. Positive (red), negative (black), illumination (white), and signal (green). Power can come from any ignition or accessories power source. In my case, I wired the power for all my gauges to the cigarette lighter. One thing to remember when doing this, is the amount of load put on the cigarette lighter circuit. A lot of people use the cigarette lighter to power extra devices. General rule of thumb is, if the fuse doesn't blow, you're set. By doing this all the gauges are on with accessories, but this is especially good if you have an aftermarket Voltmeter, so you can still monitor the battery voltage on accessories. The white wire is for the backlight, if your tacho has one which 99% should. Wire this to any positive line for cluster illumination, or to the headlight switch. The signal wire needs to go to Pin 8 of the larger connector on the back of the cluster. The wire is pink with a blue stripe. Splice into the wire.

Electric Oil PressureWhat it does: Measures oil pressure using a device called an oil pressure sender, which is screwed into the side of the engine block which creates a voltage according to the pressure, and is read by the gauge.

Wiring it up: Falcon's without oil pressure gauges in the stock cluster have a light which comes on once the oil pressure drops below a certain point. This is made possible by a oil pressure switch, not a sender. To install your oil pressure gauge, you need to do one of two things:

1. Remove the switch and replace it with a sender.
2. Fit a T-piece and have both the sender and the switch.

The switch is located on the side of the engine block. In EA-ED, this is under the intake manifold, between the coil and the dizzy. Not sure for other models, but the concept is the same. If you have a Gregory's or something of the like, that should point you in the right direction. It's a bit of a game of Twister to get to it, but it's possible.

Location of the oil pressure switch. Oil pressure sender can be seen in the red circle.

Picture of the oil pressure sender installed.

Once the sender is in, it's back into the car to wire the gauge! Again, power can come from the same place, as well as illumination. The signal wire is the same idea as the tacho. Just connect the wire from the oil pressure sensor (which you have routed through the firewall or a grommet somewhere of course ) to the signal terminal on the oil pressure gauge, and you're done!

VoltmeterWhat it does: Simply displays how many volts the battery is outputting, and therefore telling you the charge of the battery and also the load that it is being exposed to. Probably the best and most useful gauge I have in my opinion.

Wiring it up: This one is easy as. Wire up your power and illumination same as any other gauge, and you're done! Some people will argue that when the gauge is wired to the cigarette lighter for example, that it is not as accurate as direct from the battery, but unless you're hardcore about this one, the cigarette lighter is fine. You can wire directly to the battery, but make sure either the positive or the earth is switch by the key, or you will run your battery flat.

Air / Fuel RatioWhat it does: Displays a reading using the oxygen sensor which shows what sort of air / fuel mixture the car has.

Wiring it up: Relatively simple. Wire up power and illumination as per normal, and splice into the oxygen sensor in the exhaust between the headers and the cat.

Location of the oxygen sensor

A couple of things to remember:

Always disconnect the negative terminal. It takes about 2 minutes or less, and can save disasters from happening.

Make sure any part of the circuit which has exposed wire from soldering has electrical tape around each wire individually to avoid shorts.